Line data Source code
1 : /*-------------------------------------------------------------------------
2 : *
3 : * main.c
4 : * Stub main() routine for the postgres executable.
5 : *
6 : * This does some essential startup tasks for any incarnation of postgres
7 : * (postmaster, standalone backend, standalone bootstrap process, or a
8 : * separately exec'd child of a postmaster) and then dispatches to the
9 : * proper FooMain() routine for the incarnation.
10 : *
11 : *
12 : * Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group
13 : * Portions Copyright (c) 1994, Regents of the University of California
14 : *
15 : *
16 : * IDENTIFICATION
17 : * src/backend/main/main.c
18 : *
19 : *-------------------------------------------------------------------------
20 : */
21 : #include "postgres.h"
22 :
23 : #include <unistd.h>
24 :
25 : #if defined(WIN32)
26 : #include <crtdbg.h>
27 : #endif
28 :
29 : #if defined(__NetBSD__)
30 : #include <sys/param.h>
31 : #endif
32 :
33 : #include "bootstrap/bootstrap.h"
34 : #include "common/username.h"
35 : #include "port/atomics.h"
36 : #include "postmaster/postmaster.h"
37 : #include "storage/spin.h"
38 : #include "tcop/tcopprot.h"
39 : #include "utils/help_config.h"
40 : #include "utils/memutils.h"
41 : #include "utils/pg_locale.h"
42 : #include "utils/ps_status.h"
43 :
44 :
45 : const char *progname;
46 : static bool reached_main = false;
47 :
48 :
49 : static void startup_hacks(const char *progname);
50 : static void init_locale(const char *categoryname, int category, const char *locale);
51 : static void help(const char *progname);
52 : static void check_root(const char *progname);
53 :
54 :
55 : /*
56 : * Any Postgres server process begins execution here.
57 : */
58 : int
59 5226 : main(int argc, char *argv[])
60 : {
61 5226 : bool do_check_root = true;
62 :
63 5226 : reached_main = true;
64 :
65 : /*
66 : * If supported on the current platform, set up a handler to be called if
67 : * the backend/postmaster crashes with a fatal signal or exception.
68 : */
69 : #if defined(WIN32)
70 : pgwin32_install_crashdump_handler();
71 : #endif
72 :
73 5226 : progname = get_progname(argv[0]);
74 :
75 : /*
76 : * Platform-specific startup hacks
77 : */
78 5226 : startup_hacks(progname);
79 :
80 : /*
81 : * Remember the physical location of the initially given argv[] array for
82 : * possible use by ps display. On some platforms, the argv[] storage must
83 : * be overwritten in order to set the process title for ps. In such cases
84 : * save_ps_display_args makes and returns a new copy of the argv[] array.
85 : *
86 : * save_ps_display_args may also move the environment strings to make
87 : * extra room. Therefore this should be done as early as possible during
88 : * startup, to avoid entanglements with code that might save a getenv()
89 : * result pointer.
90 : */
91 5226 : argv = save_ps_display_args(argc, argv);
92 :
93 : /*
94 : * Fire up essential subsystems: error and memory management
95 : *
96 : * Code after this point is allowed to use elog/ereport, though
97 : * localization of messages may not work right away, and messages won't go
98 : * anywhere but stderr until GUC settings get loaded.
99 : */
100 5226 : MemoryContextInit();
101 :
102 : /*
103 : * Set up locale information
104 : */
105 5226 : set_pglocale_pgservice(argv[0], PG_TEXTDOMAIN("postgres"));
106 :
107 : /*
108 : * In the postmaster, absorb the environment values for LC_COLLATE and
109 : * LC_CTYPE. Individual backends will change these later to settings
110 : * taken from pg_database, but the postmaster cannot do that. If we leave
111 : * these set to "C" then message localization might not work well in the
112 : * postmaster.
113 : */
114 5226 : init_locale("LC_COLLATE", LC_COLLATE, "");
115 5226 : init_locale("LC_CTYPE", LC_CTYPE, "");
116 :
117 : /*
118 : * LC_MESSAGES will get set later during GUC option processing, but we set
119 : * it here to allow startup error messages to be localized.
120 : */
121 : #ifdef LC_MESSAGES
122 5226 : init_locale("LC_MESSAGES", LC_MESSAGES, "");
123 : #endif
124 :
125 : /*
126 : * We keep these set to "C" always, except transiently in pg_locale.c; see
127 : * that file for explanations.
128 : */
129 5226 : init_locale("LC_MONETARY", LC_MONETARY, "C");
130 5226 : init_locale("LC_NUMERIC", LC_NUMERIC, "C");
131 5226 : init_locale("LC_TIME", LC_TIME, "C");
132 :
133 : /*
134 : * Now that we have absorbed as much as we wish to from the locale
135 : * environment, remove any LC_ALL setting, so that the environment
136 : * variables installed by pg_perm_setlocale have force.
137 : */
138 5226 : unsetenv("LC_ALL");
139 :
140 : /*
141 : * Catch standard options before doing much else, in particular before we
142 : * insist on not being root.
143 : */
144 5226 : if (argc > 1)
145 : {
146 5226 : if (strcmp(argv[1], "--help") == 0 || strcmp(argv[1], "-?") == 0)
147 : {
148 0 : help(progname);
149 0 : exit(0);
150 : }
151 5226 : if (strcmp(argv[1], "--version") == 0 || strcmp(argv[1], "-V") == 0)
152 : {
153 1528 : fputs(PG_BACKEND_VERSIONSTR, stdout);
154 1528 : exit(0);
155 : }
156 :
157 : /*
158 : * In addition to the above, we allow "--describe-config" and "-C var"
159 : * to be called by root. This is reasonably safe since these are
160 : * read-only activities. The -C case is important because pg_ctl may
161 : * try to invoke it while still holding administrator privileges on
162 : * Windows. Note that while -C can normally be in any argv position,
163 : * if you want to bypass the root check you must put it first. This
164 : * reduces the risk that we might misinterpret some other mode's -C
165 : * switch as being the postmaster/postgres one.
166 : */
167 3698 : if (strcmp(argv[1], "--describe-config") == 0)
168 0 : do_check_root = false;
169 3698 : else if (argc > 2 && strcmp(argv[1], "-C") == 0)
170 0 : do_check_root = false;
171 : }
172 :
173 : /*
174 : * Make sure we are not running as root, unless it's safe for the selected
175 : * option.
176 : */
177 3698 : if (do_check_root)
178 3698 : check_root(progname);
179 :
180 : /*
181 : * Dispatch to one of various subprograms depending on first argument.
182 : */
183 :
184 3698 : if (argc > 1 && strcmp(argv[1], "--check") == 0)
185 1260 : BootstrapModeMain(argc, argv, true);
186 2438 : else if (argc > 1 && strcmp(argv[1], "--boot") == 0)
187 608 : BootstrapModeMain(argc, argv, false);
188 : #ifdef EXEC_BACKEND
189 : else if (argc > 1 && strncmp(argv[1], "--fork", 6) == 0)
190 : SubPostmasterMain(argc, argv);
191 : #endif
192 1830 : else if (argc > 1 && strcmp(argv[1], "--describe-config") == 0)
193 0 : GucInfoMain();
194 1830 : else if (argc > 1 && strcmp(argv[1], "--single") == 0)
195 628 : PostgresSingleUserMain(argc, argv,
196 628 : strdup(get_user_name_or_exit(progname)));
197 : else
198 1202 : PostmasterMain(argc, argv);
199 : /* the functions above should not return */
200 : abort();
201 : }
202 :
203 :
204 :
205 : /*
206 : * Place platform-specific startup hacks here. This is the right
207 : * place to put code that must be executed early in the launch of any new
208 : * server process. Note that this code will NOT be executed when a backend
209 : * or sub-bootstrap process is forked, unless we are in a fork/exec
210 : * environment (ie EXEC_BACKEND is defined).
211 : *
212 : * XXX The need for code here is proof that the platform in question
213 : * is too brain-dead to provide a standard C execution environment
214 : * without help. Avoid adding more here, if you can.
215 : */
216 : static void
217 5226 : startup_hacks(const char *progname)
218 : {
219 : /*
220 : * Windows-specific execution environment hacking.
221 : */
222 : #ifdef WIN32
223 : {
224 : WSADATA wsaData;
225 : int err;
226 :
227 : /* Make output streams unbuffered by default */
228 : setvbuf(stdout, NULL, _IONBF, 0);
229 : setvbuf(stderr, NULL, _IONBF, 0);
230 :
231 : /* Prepare Winsock */
232 : err = WSAStartup(MAKEWORD(2, 2), &wsaData);
233 : if (err != 0)
234 : {
235 : write_stderr("%s: WSAStartup failed: %d\n",
236 : progname, err);
237 : exit(1);
238 : }
239 :
240 : /*
241 : * By default abort() only generates a crash-dump in *non* debug
242 : * builds. As our Assert() / ExceptionalCondition() uses abort(),
243 : * leaving the default in place would make debugging harder.
244 : *
245 : * MINGW's own C runtime doesn't have _set_abort_behavior(). When
246 : * targeting Microsoft's UCRT with mingw, it never links to the debug
247 : * version of the library and thus doesn't need the call to
248 : * _set_abort_behavior() either.
249 : */
250 : #if !defined(__MINGW32__) && !defined(__MINGW64__)
251 : _set_abort_behavior(_CALL_REPORTFAULT | _WRITE_ABORT_MSG,
252 : _CALL_REPORTFAULT | _WRITE_ABORT_MSG);
253 : #endif /* !defined(__MINGW32__) &&
254 : * !defined(__MINGW64__) */
255 :
256 : /*
257 : * SEM_FAILCRITICALERRORS causes more errors to be reported to
258 : * callers.
259 : *
260 : * We used to also specify SEM_NOGPFAULTERRORBOX, but that prevents
261 : * windows crash reporting from working. Which includes registered
262 : * just-in-time debuggers, making it unnecessarily hard to debug
263 : * problems on windows. Now we try to disable sources of popups
264 : * separately below (note that SEM_NOGPFAULTERRORBOX did not actually
265 : * prevent all sources of such popups).
266 : */
267 : SetErrorMode(SEM_FAILCRITICALERRORS);
268 :
269 : /*
270 : * Show errors on stderr instead of popup box (note this doesn't
271 : * affect errors originating in the C runtime, see below).
272 : */
273 : _set_error_mode(_OUT_TO_STDERR);
274 :
275 : /*
276 : * In DEBUG builds, errors, including assertions, C runtime errors are
277 : * reported via _CrtDbgReport. By default such errors are displayed
278 : * with a popup (even with NOGPFAULTERRORBOX), preventing forward
279 : * progress. Instead report such errors stderr (and the debugger).
280 : * This is C runtime specific and thus the above incantations aren't
281 : * sufficient to suppress these popups.
282 : */
283 : _CrtSetReportMode(_CRT_ERROR, _CRTDBG_MODE_FILE | _CRTDBG_MODE_DEBUG);
284 : _CrtSetReportFile(_CRT_ERROR, _CRTDBG_FILE_STDERR);
285 : _CrtSetReportMode(_CRT_ASSERT, _CRTDBG_MODE_FILE | _CRTDBG_MODE_DEBUG);
286 : _CrtSetReportFile(_CRT_ASSERT, _CRTDBG_FILE_STDERR);
287 : _CrtSetReportMode(_CRT_WARN, _CRTDBG_MODE_FILE | _CRTDBG_MODE_DEBUG);
288 : _CrtSetReportFile(_CRT_WARN, _CRTDBG_FILE_STDERR);
289 : }
290 : #endif /* WIN32 */
291 :
292 : /*
293 : * Initialize dummy_spinlock, in case we are on a platform where we have
294 : * to use the fallback implementation of pg_memory_barrier().
295 : */
296 5226 : SpinLockInit(&dummy_spinlock);
297 5226 : }
298 :
299 :
300 : /*
301 : * Make the initial permanent setting for a locale category. If that fails,
302 : * perhaps due to LC_foo=invalid in the environment, use locale C. If even
303 : * that fails, perhaps due to out-of-memory, the entire startup fails with it.
304 : * When this returns, we are guaranteed to have a setting for the given
305 : * category's environment variable.
306 : */
307 : static void
308 31356 : init_locale(const char *categoryname, int category, const char *locale)
309 : {
310 31356 : if (pg_perm_setlocale(category, locale) == NULL &&
311 0 : pg_perm_setlocale(category, "C") == NULL)
312 0 : elog(FATAL, "could not adopt \"%s\" locale nor C locale for %s",
313 : locale, categoryname);
314 31356 : }
315 :
316 :
317 :
318 : /*
319 : * Help display should match the options accepted by PostmasterMain()
320 : * and PostgresMain().
321 : *
322 : * XXX On Windows, non-ASCII localizations of these messages only display
323 : * correctly if the console output code page covers the necessary characters.
324 : * Messages emitted in write_console() do not exhibit this problem.
325 : */
326 : static void
327 0 : help(const char *progname)
328 : {
329 0 : printf(_("%s is the PostgreSQL server.\n\n"), progname);
330 0 : printf(_("Usage:\n %s [OPTION]...\n\n"), progname);
331 0 : printf(_("Options:\n"));
332 0 : printf(_(" -B NBUFFERS number of shared buffers\n"));
333 0 : printf(_(" -c NAME=VALUE set run-time parameter\n"));
334 0 : printf(_(" -C NAME print value of run-time parameter, then exit\n"));
335 0 : printf(_(" -d 1-5 debugging level\n"));
336 0 : printf(_(" -D DATADIR database directory\n"));
337 0 : printf(_(" -e use European date input format (DMY)\n"));
338 0 : printf(_(" -F turn fsync off\n"));
339 0 : printf(_(" -h HOSTNAME host name or IP address to listen on\n"));
340 0 : printf(_(" -i enable TCP/IP connections (deprecated)\n"));
341 0 : printf(_(" -k DIRECTORY Unix-domain socket location\n"));
342 : #ifdef USE_SSL
343 0 : printf(_(" -l enable SSL connections\n"));
344 : #endif
345 0 : printf(_(" -N MAX-CONNECT maximum number of allowed connections\n"));
346 0 : printf(_(" -p PORT port number to listen on\n"));
347 0 : printf(_(" -s show statistics after each query\n"));
348 0 : printf(_(" -S WORK-MEM set amount of memory for sorts (in kB)\n"));
349 0 : printf(_(" -V, --version output version information, then exit\n"));
350 0 : printf(_(" --NAME=VALUE set run-time parameter\n"));
351 0 : printf(_(" --describe-config describe configuration parameters, then exit\n"));
352 0 : printf(_(" -?, --help show this help, then exit\n"));
353 :
354 0 : printf(_("\nDeveloper options:\n"));
355 0 : printf(_(" -f s|i|o|b|t|n|m|h forbid use of some plan types\n"));
356 0 : printf(_(" -O allow system table structure changes\n"));
357 0 : printf(_(" -P disable system indexes\n"));
358 0 : printf(_(" -t pa|pl|ex show timings after each query\n"));
359 0 : printf(_(" -T send SIGABRT to all backend processes if one dies\n"));
360 0 : printf(_(" -W NUM wait NUM seconds to allow attach from a debugger\n"));
361 :
362 0 : printf(_("\nOptions for single-user mode:\n"));
363 0 : printf(_(" --single selects single-user mode (must be first argument)\n"));
364 0 : printf(_(" DBNAME database name (defaults to user name)\n"));
365 0 : printf(_(" -d 0-5 override debugging level\n"));
366 0 : printf(_(" -E echo statement before execution\n"));
367 0 : printf(_(" -j do not use newline as interactive query delimiter\n"));
368 0 : printf(_(" -r FILENAME send stdout and stderr to given file\n"));
369 :
370 0 : printf(_("\nOptions for bootstrapping mode:\n"));
371 0 : printf(_(" --boot selects bootstrapping mode (must be first argument)\n"));
372 0 : printf(_(" --check selects check mode (must be first argument)\n"));
373 0 : printf(_(" DBNAME database name (mandatory argument in bootstrapping mode)\n"));
374 0 : printf(_(" -r FILENAME send stdout and stderr to given file\n"));
375 :
376 0 : printf(_("\nPlease read the documentation for the complete list of run-time\n"
377 : "configuration settings and how to set them on the command line or in\n"
378 : "the configuration file.\n\n"
379 : "Report bugs to <%s>.\n"), PACKAGE_BUGREPORT);
380 0 : printf(_("%s home page: <%s>\n"), PACKAGE_NAME, PACKAGE_URL);
381 0 : }
382 :
383 :
384 :
385 : static void
386 3698 : check_root(const char *progname)
387 : {
388 : #ifndef WIN32
389 3698 : if (geteuid() == 0)
390 : {
391 0 : write_stderr("\"root\" execution of the PostgreSQL server is not permitted.\n"
392 : "The server must be started under an unprivileged user ID to prevent\n"
393 : "possible system security compromise. See the documentation for\n"
394 : "more information on how to properly start the server.\n");
395 0 : exit(1);
396 : }
397 :
398 : /*
399 : * Also make sure that real and effective uids are the same. Executing as
400 : * a setuid program from a root shell is a security hole, since on many
401 : * platforms a nefarious subroutine could setuid back to root if real uid
402 : * is root. (Since nobody actually uses postgres as a setuid program,
403 : * trying to actively fix this situation seems more trouble than it's
404 : * worth; we'll just expend the effort to check for it.)
405 : */
406 3698 : if (getuid() != geteuid())
407 : {
408 0 : write_stderr("%s: real and effective user IDs must match\n",
409 : progname);
410 0 : exit(1);
411 : }
412 : #else /* WIN32 */
413 : if (pgwin32_is_admin())
414 : {
415 : write_stderr("Execution of PostgreSQL by a user with administrative permissions is not\n"
416 : "permitted.\n"
417 : "The server must be started under an unprivileged user ID to prevent\n"
418 : "possible system security compromises. See the documentation for\n"
419 : "more information on how to properly start the server.\n");
420 : exit(1);
421 : }
422 : #endif /* WIN32 */
423 3698 : }
424 :
425 : /*
426 : * At least on linux, set_ps_display() breaks /proc/$pid/environ. The
427 : * sanitizer library uses /proc/$pid/environ to implement getenv() as it wants
428 : * to work independent of libc. When just using undefined and alignment
429 : * sanitizers, the sanitizer library is only initialized when the first error
430 : * occurs, by which time we've often already called set_ps_display(),
431 : * preventing the sanitizer libraries from seeing the options.
432 : *
433 : * We can work around that by defining __ubsan_default_options, a weak symbol
434 : * libsanitizer uses to get defaults from the application, and return
435 : * getenv("UBSAN_OPTIONS"). But only if main already was reached, so that we
436 : * don't end up relying on a not-yet-working getenv().
437 : *
438 : * As this function won't get called when not running a sanitizer, it doesn't
439 : * seem necessary to only compile it conditionally.
440 : */
441 : const char *__ubsan_default_options(void);
442 : const char *
443 0 : __ubsan_default_options(void)
444 : {
445 : /* don't call libc before it's guaranteed to be initialized */
446 0 : if (!reached_main)
447 0 : return "";
448 :
449 0 : return getenv("UBSAN_OPTIONS");
450 : }
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